Truss arm and crane

The utility model discloses a truss arm and a crane, relates to the field of engineering machinery, and is used for optimizing the structure of the truss arm. The truss arm comprises a rectangular supporting frame, web members and first locking pieces. The rectangular supporting frame is provided with at least two fixing positions. The web members are connected to form a deformable shape, and theends of the web members are hinged to the rectangular supporting frame. And the end parts of at least two web members are connected with the rectangular support frame in a sliding manner so as to realize adjustable mounting positions. The first locking piece is at least partially and selectively installed on at least one of the two fixing positions. The first locking piece is located on the sliding path and located outside the sliding connection matching face, and the first locking piece is used for locking the end of the web member and the rectangular supporting frame so as to prevent the webmember from being in slid